1. Field of the Invention
The present invention relates to a liquid ejection apparatus and a liquid ejection method using the liquid ejection apparatus. More particularly, the invention relates to a liquid ejection apparatus and a liquid ejection method for ejecting liquid inside a tank towards a peripheral wall of the tank and for distributing the liquid onto an inner peripheral surface of the tank peripheral wall and/or into a space above the liquid surface inside the tank.
2. Description of the Related Art
In fermentation and culturing, the fermenting liquids and culturing liquids are both very prone to foaming. Due to agitation during the process, there is a considerable amount of foaming so that operability is often impaired. In order to inhibit such foaming, and to disperse the temporarily created foam, defoaming agents such as silicone are added to both the fermenting liquids and culturing liquids. The addition of such defoaming agents however not only involves significant cost, but also poses a risk adversely affecting the fermentation and culturing processes, because these defoaming agents are in themselves foreign substances to the liquids. In addition, the defoaming agents are mixed with the product as impurities so that the quality of the product is degraded. Therefore the defoaming agent must be removed from the product and this removal of the defoaming agent takes time. Furthermore the defoaming agents added to both the fermenting liquids and culturing liquids are mixed in the waste liquid and thus impede the treatment of the waste liquid. Hence the addition of defoaming agents is an undesirable means, which should be avoided as much as possible.
Moreover, in order to disperse the foam, experiments have been made to collapse the foam with shearing forces using mechanical means involving turning a disk within the foam layer on the liquid surface, or turning a hollow cylindrical body of truncated cone shape with a lower opening of the large diameter facing the liquid surface inside the tank. However with such means, not only is a considerable amount of energy required, but also the foam is often only merely broken up finely, and is not ultimately dispersed.
Another problem is that the inner peripheral surface of the peripheral wall of the agitating tank used as both a fermenting tank and a culturing tank becomes contaminated by microorganisms or solid raw materials or products being deposited thereon. This often causes a decrease in reaction yield or a reduction in heat transfer coefficient of the agitating tank peripheral wall. In this case, it is practically impossible to wash the inner peripheral surface of the inner wall of the agitating tank in order to remove the extraneous matter from the inner peripheral surface of the agitating tank without stopping the operation in the agitating tank.
Yet another problem arises with agitating tanks which are used as crystallization tanks or the like, when apparatus such as jackets and coiled pipes, and multi-tube heating units are respectively provided on the outer peripheral surface of the peripheral wall of the agitating tank, and/or are immersed into the liquid inside the agitating tank, as apparatus for heating or cooling the liquid inside the agitating tank, so that the inner peripheral surface of the peripheral wall and/or the surface of the portion of the heating or cooling apparatus which is immersed into the liquid becomes a heat transmission surface. In this case there is often the situation where the volume of liquid inside the agitating tank decreases due for example to evaporation, so that with time, the liquid level inside the agitating tank drops, and hence the heat transfer area of the heating or cooling apparatus cannot be effectively utilized.
In order to increase and hence recover the reduced heat transfer area, there are a method wherein fresh liquid is supplied to the tank so that the liquid surface is raised; or a method wherein the remaining liquid inside the tank is circulated by means of a pump provided outside of the tank until the liquid is distributed onto the inner peripheral surface of the tank peripheral wall. The former wherein fresh liquid is supplied to the tank, has the defect that there is an abrupt change in the composition of the liquid inside the tank, requiring an abrupt change in operational conditions to counter this, and also the quality of the product changes. Moreover, the latter has the defect that it requires a pump and piping for circulating the remaining liquid, so that, after operation, residual liquid remains in the tank as well as inside the piping. Consequently, the former means cannot be practically employed. Moreover, the latter requires improvements in order to be practical. Accordingly, means which can be put into practice to solve the defect that the heat transfer area cannot be effectively used have yet to be found.
When desired, in order to evaporate the liquid inside the agitating tank, normally methods are adopted which involve immersing a heating device into the liquid, or mounting a heating device on the outer peripheral surface of the agitating tank. The liquid is heated thereby to cause evaporation from the liquid surface either while agitating or not agitating the liquid. The methods are sometimes effected under reduced pressure or under pressure. With these methods there is the defect that heat in the space above the surface of the liquid which is heated by the heating device only heats the surface of the liquid and hence cannot be effectively utilized, and that the heating of the liquid inside the tank is limited to the contact surface of the heating device and the liquid surface. Accordingly, the heat from the heating device cannot be effectively utilized. Hence, the rate of the evaporation of the liquid is slow.
The present inventors, by using only mechanical agitation, have effectively overcome all of the heretofore various defects such as; the uncertain defoaming using shearing forces, the contamination of the inner peripheral surface of the agitating tank, the reduction in heat transfer area at the inner peripheral surface of the agitating tank, the contamination and reduction of the heat transfer area of the heating or cooling apparatus provided inside the tank, and the delayed evaporation of the liquid inside the agitating tank. Moreover, the present inventors made a thorough study on apparatus and methods enabling with good efficiency and reliable defoaming, all of washing of the inner peripheral surface of the agitating tank, retention of the heat transfer area on the inner peripheral surface of the agitating tank, washing of the heat transfer surface of the heating or cooling apparatus, and promotion of evaporation of the liquid inside the agitating tanks.
It is an object of the present invention to take into consideration the above situation with conventional liquid ejection apparatus and provide an improved liquid ejection apparatus and improved liquid ejection method using the liquid ejection apparatus.
The present inventors, with these apparatus and methods, have found that, in order to distribute the liquid inside the tank over the widest possible area of the inner peripheral surface of the tank, the liquid as much as possible is ejected from the liquid-transporting body and is allowed to reach as high as possible on the inner peripheral surface of the tank. Therefore, if the inclination angle of the liquid-transporting body remains the same, the rotational speed of the agitating shaft on which the liquid-transporting body is mounted can be increased in accordance with the drop in the liquid level as the liquid depth becomes shallower. In this way, the construction can be simplified. The present invention has been achieved based on this new knowledge.
According to a first aspect of the invention there is provided a liquid ejection apparatus wherein a liquid-transporting body having a lower opening and an upper opening at respective lower and upper end portions thereof is mounted on an agitator shaft by means of an attachment device, and the liquid-transporting body is revolved about the agitator shaft with the lower opening of the liquid-transporting body immersed beneath a liquid surface in a tank, and the upper opening of the liquid-transporting body exposed from the liquid surface. The revolving speed is changed in accordance with a change in the liquid depth inside the tank. The liquid-transporting body raises the liquid in the immersed portion of the liquid-transporting body, and ejects the liquid from the upper opening of the liquid-transporting body until the liquid is distributed onto an inner peripheral surface of a tank and/or into a space above the liquid surface in the tank.
According to a second aspect of the invention there is provided a method of ejecting a liquid wherein the liquid-transporting body of the liquid ejection apparatus according to the first aspect of the invention is revolved about the agitator shaft with the lower opening immersed beneath the liquid surface and the upper opening exposed from the liquid surface, so that the liquid-transporting body raises the liquid at the immersed portion of the liquid-transporting body, and ejects the liquid from the upper opening of the liquid-transporting body, until the liquid is distributed onto the inner peripheral surface of the tank and/or into the space above the liquid surface in the tank.
With the present invention, unless otherwise defined, the terms upper and lower are respectively defined as a position far from the bottom of the liquid and a position near to the bottom of the liquid.
The attachment device is for mounting the liquid-transporting body on the agitator shaft. The attachment device may be a rod, a square bar, a shaped steel body, a plate formed with one or more openings (referred to hereunder as a punched plate), or a non-punched plate. With the non-punched plate and punched plate, preferably these are respectively attached horizontally to the agitator shaft so that when turned within a liquid, the fluid resistance does not become excessively large. The attachment device or a part thereof may be used as an agitator for the liquid when immersed in the liquid in the tank. Those plates are normally respectively positioned approximately on a radius or diameter in the revolution plane. Moreover, the horizontal punched plate and the horizontal non-punched plate are positioned with their center approximately coincided with the center of the revolution plane. The number of the plates may be one or more. When a plurality are used, then normally each member is positioned either on the same revolution plane or on revolution planes differing from each other. Normally only one liquid transporting body is attached to one attachment device on a radius between the agitator shaft and the circumferential edge. However, there is no objection to providing a plurality of liquid-transporting bodies on this radius.
With the liquid ejection apparatus of the present invention, the rotational speed of the agitating shaft is changed corresponding to the change in the liquid depth inside the tank. For example the rotational speed of the agitating shaft is increased as the liquid depth inside the tank becomes shallower so that the turning speed of the liquid-transporting body is increased. To achieve this, preferably the liquid depth inside the tank is detected, and the detected liquid depth is transmitted, for example, via a controller or a computer to a rotational speed change apparatus such as an electric motor installed in the prime mover for driving the agitating shaft, and the rotational speed of the prime mover is then adjusted to a rotational speed corresponding to the liquid depth. Here, the agitator shaft and the prime mover for driving the agitator shaft are directly connected, or a indirectly connected via a belt or a gear or the like.
Load of the prime movers such as electric motors and torque of the agitator shaft become smaller as liquid depth becomes shallower. Change of the load on the electric motor and the torque in the agitator shaft, corresponding to change of liquid depth, may be detected in place of detecting the liquid depth. That is to say, electric current values respectively are set beforehand corresponding to predetermined sizes of loads on the electric motor and torques of the agitator shaft (the set electric current values are referred to hereunder as the set current values). In the case where the respective sizes of the load on the electric motor and the torque of the agitator shaft are reduced with a drop in liquid level until the electric current supplied to the electric motor drops, the supply current to the electric motor to compensate for a difference between the set current value and the dropped current value is increased, thereby increasing the rotational speed of the electric motor. When the current supplied to the electric motor attains the set current value, then the electric motor is restored to the rotational speed corresponding to the set current value. In this case however, an upper limit for the rotational speed of the electric motor should be set beforehand so that this does not increase to a rotational speed which exceeds the capacity of the liquid ejection apparatus. In order to change the rotational speed of the electric motor corresponding to the change of liquid depth, a known means for this can be applied.
As a detector of liquid depth inside the tank, normally liquid level indicators can be suitably used. The liquid level indicator detects the change in the height of the liquid level inside the tank. There is no particular limitation to the type of instrument or apparatus, provided this is able to transmit the detected liquid depth. As a suitable representative example, there is a differential pressure transducer such as a differential pilot, or a float transmitter such as a float pilot. For the liquid depth detector, a commercial product may be used. Moreover, it is also possible to detect the liquid depth inside the tank by eyes, and to non-automatically adjust the rotational speed of the electric motor for driving the agitator shaft, corresponding to the observation.
Normally for the detection of the torque of the agitator shaft and the load on the electric motor, a torque meter and a dynamometer are suitably used respectively. For the torque meter and the dynamometer, respective commercial products may be used.
As a representative example of a suitable rotational speed change apparatus, there is an electric motor incorporating an inverter (referred to hereunder as an inverter speed changer), a Beier Variator (trade name) speed changer, a RINGCONE (trade name) speed changer and the like. Especially the inverter speed changer is preferred. An inverter involves a system or apparatus for converting DC current into AC current. The inverter speed changer changes the primary frequency of an AC electric motor using an inverter, to thereby change the rotational speed of the electric motor. The inverter preferably has a motor stall prevention function. By means of the motor stall prevention function of the inverter, the change of the liquid depth, and the change of the respective sizes of the load on the electric motor and the torque in the agitator shaft can be detected, and the rotational speed of the electric motor is then controlled so that the respective sizes of the load on the electric motor and the torque in the agitator shaft become constant. Hence stall occurring during operation of the liquid ejection apparatus can be prevented. As the rotational speed change apparatus, a commercial product can be used.
By means of the rotational speed change apparatus, the respective sizes of the load on the electric motor and the torque in the agitator shaft can be automatically controlled to become constant. Therefore, for example in the case where the rotational speed change apparatus is a Beier Variator speed changer, an electric type automatic remote control unit is installed instead of a manual speed change handle. A signal from the dynamometer or the torque meter is sent to an adjuster of the electric type automatic remote control unit. When the electric current corresponding to the respective sizes of the load on the electric motor and the torque in the agitator shaft sent by this signal differs from a previously set current value, a signal for this difference is sent to a speed setter, and, corresponding to this signal, an electric signal is sent from the speed setter to the electric type automatic remote control unit, to sequentially turn or reverse turn the speed change handle. As a result, the rotational speed of the Beier Variator speed changer is increased or decreased, to thereby increase or decrease the rotational speed of the electric motor.
If the torque of the agitator shaft or the load on the electric motor sent by the signal from the torque meter or dynamometer in the adjuster of the electric type automatic remote control unit is not different from the previously set torque or load, then the rotational speed of the Beier Variator speed changer, that is to say the rotational speed of the electric motor does not change becoming a constant speed rotation. Moreover, for the controller, normally a digital controller is used, but an analogue controller may also be used.
Here, the controller is also referred to as a blind controller. This is a control device which has a function for automatically adjusting the control amount in the automatic control apparatus. It comprises a setting section and an adjusting section. It makes adjustment by generating a signal such that a difference between a value corresponding to a signal (control amount) supplied from outside, for example the size of the torque, and a value previously set in the setting section, is reduced by the joint use in the adjusting section of three of proportional action; differential action or integral action; or proportional action, differential action and integral action. For the controller, a commercial product can be used. Moreover, the controller can be connected to an inverter. In this case if there is no stall prevention function of the inverter, the frequency can be changed by the signal from the controller, and hence this is preferable.
As the liquid-transporting body, it is sufficient if liquid can pass therethrough. Normally, this is a tubular body, a plate body, a gutter body (the tubular body, the plate body and the gutter body are generically referred to hereunder as slim type liquid-transporting bodies), a bottomless open circular tube (referred to hereunder as a tube type liquid-transporting body) with a longitudinal axis thereof coincided with the agitator shaft, and a bottomless inverted truncated cone open tube body (referred to hereunder as an inverted truncated cone type liquid-transporting body) (both the tube type liquid-transporting body and the inverted truncated cone type liquid-transporting body are generically referred to hereunder as stout type liquid-transporting bodies). With the inverted truncated cone type liquid-transporting body, the wall may be curved at a small curvature towards the inside. Preferred liquid-transporting body is an open pipe gutter having the same shape as a trough along the edge of the eaves of a building to carry off rainwater.
For the slim type liquid-transporting body, for example the devices as illustrated in JP 6-335627A may be used.
The liquid-transporting bodies are respectively provided with a lower opening and an upper opening at their respective lower and upper portions. The lower opening and the upper opening are respectively opened beneath the liquid surface, and into the space above the liquid surface inside the tank, respectively, giving an inlet and outlet for the liquid inside the tank.
With the slim type liquid-transporting body, the size of the upper opening and the lower opening may be the same as each other, or may be different from each other. Having the lower opening larger than the upper opening is the most desirable. In this case, the ratio between the sizes of the lower opening and the upper opening may be appropriately selected based on the size of the inclination angle of the liquid-transporting body, the revolutional speed, the lift of the ejection liquid, the ejection amount, and the type of liquid.
One or a plurality of slim type liquid-transporting bodies may be arranged on one attachment device. In the case where a plurality of slim type liquid-transporting bodies are arranged on one attachment device, the upper opening pair and the lower opening pair of the slim type liquid-transporting bodies may be respectively opened either to substantially the same revolutional plane as each other, or to different revolutional planes to each other. The former is however preferable.
There is no particular limitation on the material of the liquid-transporting body. Normally this is made from a metal such as steel or stainless steel, from a transparent or opaque composite resin, from a metal with good corrosion resistance or from plastics, or from a corrosion resistant material such as glass and ceramic.
In particular, in the case where the liquid-transporting bodies are respectively the plate body, the gutter body, and the stout type liquid-transporting body (discussed later), they are preferably made of metals such as steel or stainless steel, and at least the inside and outside peripheral surfaces thereof are coated or lined with a substance having a high corrosion resistance such as a synthetic resin like polytetrafluoroethylene, or with glass, ceramic or the like.
The tubular body may be any of: a cylindrical body with the size of the diameter constant, an angled tubular body with the length of the sides or the length of the diagonal lines constant, a circular conical or an angled conical bottomless open tubular body (referred to hereunder as a conical tubular body) with the size of the diameter etc. successively changing with progress from one end to the other (hereunder the respective diameters of the tubular body and the circular conical tubular body, and the respective sides or the diagonals of the angled tubular bodies and angled conical tubular bodies are also generally referred to as xe2x80x9cdiameters etc.xe2x80x9d). With the conical tubular body, normally this is used as a conical tubular body with the small diameter upward.
The tubular body may be a straight pipe throughout. However the upper portion and central portion may be straight with the lower portion curved. Moreover, the overall shape when viewed from the side may be an approximate S-shape. In practice it is desirable to make the direction of the curved portion slightly away from the vertical or downward from the horizontal. Furthermore as desired, the upper portion of the straight pipe portion may be bent at an incline upward or at an incline downward. They may also be formed by connecting a separate pipe to the tip end of the straight pipe section of the tubular body by welding or threaded attachment or the like.
The bent portion of the tubular body is formed so that, at the junction with the straight pipe portion, on the revolution plane of this junction, this makes an angle of essentially 0xc2x0 to 90xc2x0 with respect to the radial direction of the revolution plane. That is to say, the bent portion is formed so as to lie along the radius of the revolution plane, or along a circumference with a radius of the distance from the agitator shaft to the junction, or along a direction tangential to the circumference. Moreover, the overall tubular body may be curved along an arc of a circle of the same radius as the distance from the agitator shaft to the attachment position of the tubular body. Furthermore, the overall tubular body may be a straight tube shape overall when viewed from above or below the revolution plane, and may be attached to the attachment device so as to be essentially 0xc2x0 to 90xc2x0 with respect to the radial direction of the revolution plane, as mentioned before. In the case where the liquid-transporting body is either one of a gutter body and a plate body, the arrangement is substantially no different to that for the tubular body.
There is no particular restriction to the respective shapes of the upper and lower openings of the tubular body. Normally these are for example a circular shape such as a circle, a flat oval or an ellipse, or a polygon shape such as a triangle, a square, a rectangle, a rhombus, a hexagon, or an octagon. The respective shapes of the upper and lower openings may be substantially the same as each other or may be different from each other. Preferably, the lower opening is larger than the upper opening.
The upper opening of the tubular body may be covered with a perforated plate, and may be a shower plate type with the upper opening portion as a funnel. In this case, the total area of the plurality of holes is the area of the upper opening. The upper opening portion of the tubular body may be closed off (blind). Here a plurality of holes may be pierced for the opening to give a spray type. In this case, the total area of the plurality of holes is the area of the upper opening.
The plate body serving as the slim type liquid-transporting body, may be for example a straight shape or an elongate S-shape in overall side view, while the overall shape in plan view may be for example an elongated trapezoid or rectangle, or a shape where these are curved with a slight curvature. Moreover, the plate body may be twisted such that the side of the lower portion or lower edge which follows in the revolving direction is upward.
The respective upper edge and lower edge of the plate body or the gutter body (the slim type liquid-transporting bodies) correspond respectively to the upper opening and lower opening of the tubular bodies (the slim type liquid-transporting bodies). The respective upper edge and lower edge of the plate body or gutter body (the slim type liquid-transporting bodies) are also referred to hereunder as the upper opening and the lower opening.
The gutter body serving as the slim type liquid-transporting body corresponds to a tubular body with a top face removed to form an elongate opening (this opening is referred to hereunder as a top face opening). The shape of the central transverse section, and the respective shapes of the upper opening and lower opening in the upper end rim or upper end portion and lower end rim or lower end portion have no particular limitation. It is also possible to make them a left/right symmetrical or a left/right non-symmetrical shape (referred to hereunder as symmetrical shape and non-symmetrical shape respectively), but in practice the former is preferable.
As a representative example of the symmetrical shape, the following can be considered; a circumference with part of an arc missing (referred to hereunder as a cut out circumference), a semi-circle, a semi-elliptical circumference, a half oval, a U-shape, a V-shape, polygon shapes such as; a trapezoid, a square, a rectangle, a modified pentagon shape wherein a right octagon shape has been divided in two by a straight line connecting a first point and a fifth point thereof, and a modified hexagon shape where a right octagon shape has been divided in two by a straight line connecting the central points of respective first and fifth sides thereof, as well as shapes wherein the head angles of the polygon shapes are rounded and/or the sides are bent outwards with a small curvature (referred to hereunder as substantially polygon shapes) and one side is removed.
As a representative example of the non-symmetrical shape, there are for example shapes where one of the peripheries or the sides at the edge (referred to hereunder as the opening edge) corresponding to the two peripheral edges of the opening of the beforementioned symmetrical shapes is extended (these symmetrical shapes and non-symmetrical shapes are referred to hereunder as open shapes).
The gutter body may be made as an equal sided V-shaped steel body, an H-shaped steel body, or as a C-shaped steel body wherein the transverse section is a quadrilateral of square or rectangular shape with one side missing or is circular. The C-shaped steel body is preferable. The equal sided V-shaped steel body gives a gutter body having a right angled L-shape opening. The H-shaped steel body gives a gutter body having respectively a square or rectangular shaped opening with one side missing. The C-shaped steel body wherein the transverse section shape is a quadrilateral gives a gutter body having a quadrilateral shape opening with one portion of one side missing, while the C-shaped steel body wherein the transverse section shape is circular gives a gutter body having a cut-out circumference opening. Moreover, in coating or lining the gutter body which in itself is known, then prior to coating or lining, the edges of the top surface openings are preferably rounded, or enlarged into a column shape.
With the gutter body, the respective opening areas of the upper opening and the lower opening are defined as the areas which obtain the through flow of liquid along the concavity (inner peripheral surface) of the gutter body. With the respective opening areas of the upper opening and lower opening of the gutter body, in the case where the shapes of the upper opening and lower opening are an open shape with left-right symmetry, then this is the area enclosed by the shape and a straight line connecting the opposite opening edges. In the case where the transverse section shape of the upper end rim or upper end portion and lower end rim or lower end portion of the upper opening and lower opening is a non-symmetrical open shape, then this is the area enclosed by the shape and a straight line connecting the extended portion edge and the other opening edge, or the area enclosed by the shape and a straight line connecting the opposite opening edges excluding the extended portion.
There is no particular restriction on the shape of the side of the gutter body (referred to hereunder as the side shape), however overall, normally this is a straight line, a curve which is bent at a small curvature so as to protrude upward or downward, or an S-shape wherein the upper end and/or the lower end of a straight line or the beforementioned curve are further extended in the horizontal direction or downward of the horizontal direction. For the curve, a parabola is preferable. Among other things, a straight line is preferable since this simplifies formation of the gutter body. Moreover, a curve which is bent so as to protrude downwards is preferable since this enables an increase in the liquid discharge distance and/or the discharge amount. A parabola which is bent so as to protrude downwards is particularly desirable.
There is no particular restriction on the shape of gutter body as seen from the front (referred to hereunder as the front shape), however overall, normally this is a straight line, a curve which is bent at a small curvature in the transverse direction (a direction parallel with the revolutional plane of the gutter body; defined similarly hereunder), or an S-shape wherein the upper end and/or the lower end of a straight line or the beforementioned curve are further extended in the transverse direction. However among other things a straight line is preferable.
As with the beforementioned side shape and front shape of gutter body, there is no particular restriction on the shape as seen from above or beneath (referred to hereunder as the plan shape). Overall, this is normally a straight line, a curve which is bent at a small curvature towards the direction of revolution of the gutter body or the opposite direction, or an S-shape wherein the upper end and/or the lower end of a straight line or the beforementioned curve are further extended in the transverse direction. However, among them, a straight line is preferable.
There is no particular limit to the length of the gutter body. However longer is better, and preferably this is longer than the depth of the liquid layer where the liquid transporting body is installed. Moreover, the lengths of a plurality of gutter bodies attached to the attachment device may be the same as each other, or may be different from each other.
Two or more gutter bodies may be connected side-by-side. For example, two gutter bodies are arranged in parallel so that one of edges of opening of a gutter body is connected alongside to that of another gutter body next positioned. Instead, a partition wall may be positioned in an axial direction inside the gutter body to form two separate canals.
In order to dispersingly eject the liquid from the upper opening of the gutter body as a spray, as minute droplets, or as a fine flow, then the whole of the upper opening of the gutter body may be covered with a perforated plate drilled with a plurality of holes, or with a mesh. This too is preferable. With respect to the perforated plate, the plurality of holes may be pierced regularly or irregularly. There is no particular restriction on the shape and number of holes. As a representative example of the shape of the holes, these may be circular, elliptical, square, or rectangular. As to the gutter body, the upper opening may be closed off by a plate so that a gap is formed along the inner peripheral surface of the gutter body. Furthermore, the top face opening of the gutter body, may be covered with an opaque or transparent cover which is removable. Moreover, a deflector plate may be provided spaced apart from the upper opening of the gutter body, to thereby abruptly change the direction of the liquid ejected therefrom.
Furthermore, the gutter body may be twisted sufficiently to obtain raising of the liquid. Moreover, the gutter body may be free to turn about the longitudinal axis thereof. In these cases, the angle through which the gutter body is twisted or turned about itself is appropriately selected depending for example on the shape of the opening and the size of the inclination angle of the gutter body, the viscosity of the liquid in the container, and the revolutional speed of the gutter body. In the case of the latter, the gutter body may be mounted on the attachment device so as to be able to be turned about itself. In this case the gutter body may also be secured after being turned to an optional deviation angle. Moreover, this can be turned about itself automatically depending on the revolutional speed of the gutter body. In this case, the gutter body is mounted on the agitator shaft so as to be freely rotatable about itself.
Furthermore, the gutter body is attached to the agitator shaft via the attachment device with the concavity or the top face opening of the gutter body facing inside of a revolving circle thereof, preferably towards the agitator shaft or the revolution direction. The extent that the concavity or the top face opening of the gutter body faces the agitator shaft is indicated by a deviation angle. The deviation angle is defined as being the same as the declination angle. Here, if A, B and C are optionally selected in order from a preceding area towards the following area according to revolution direction, in the horizontal cross-section at the openings of the gutter body or in the revolution plane of the gutter body, and D is the rotation axis (the center of the agitator shaft; defined similarly hereunder) on the same cross-section as above. These points A, B, C, and D satisfy the following conditions:
(1) the distance between B and D is greater than or equal to the distance between C and D;
(2) the angle ABD subtended by the line segment AB and the base line BD, and the angle CBD subtended by the line segment BC and the base line BD are named as xcex81 and xcex82, respectively.
A. in the case where the gutter body is revolved in the clockwise direction or to the right direction about the axis D,
for xcex81, (+) sign is given, when it is within the preceding area before the base line BD, while (xe2x88x92) sign is given when it is within the following area behind the base line BD; but for xcex82, (xe2x88x92) sign is given, when it is within a following area behind the base line BD while (+) sign is given when it is within a preceding area before the base line BD;
B. in the case where the gutter body is revolved in the counter-clockwise direction or to the left direction, the same signs as in A above are given to xcex81 and xcex82, respectively, i.e., (+) sign is given to xcex81 when xcex81 is within a preceding area before the base line BD.
Preferable range of xcex81 and xcex82 are
xe2x88x9275xc2x0xe2x89xa6xcex81xe2x89xa6110xc2x0
xe2x88x9275xc2x0xe2x89xa6xcex82xe2x89xa6110xc2x0.
Moreover, the declination angle is shown as (xcex81+xcex82)/2. Consequently, the declination angle is zero when the respective absolute angles of xcex81 and xcex82 are equal to each other.
The declination angle is appropriately selected in the beforementioned range, depending for example on the shape of gutter body itself and the opening shape, the opening area ratio between the upper and the lower openings, and the use of the ejected liquid.
When attaching the gutter body to the attachment device, the arrangement must be such that the attachment device does not obstruct the rising of the liquid within the concavity of the gutter body.
The turning about the revolving axis of the plate liquid-transporting body is the same as for the gutter body liquid-transporting body.
With the slim type liquid-transporting body, one of a plurality of through holes may be pierced in the wall thereof, and this is preferable. A plate may be fitted spaced apart from the outer side of the through hole (the side close to the peripheral wall of the tank; defined similarly hereunder). By means of this plate, the ejection direction of the ejection liquid ejected from the upper opening can be changed. Furthermore, a pipe and spray nozzle may be attached to the slim type liquid-transporting body, radiating out from the outside of the through hole (the opposite side to the agitator shaft; defined similarly hereunder). The liquid passing along the slim type liquid-transporting body may also be ejected to the outside from a through hole pierced in the wall of the slim type liquid-transporting body. By selecting the size of this through hole, then a desired quantity of liquid passing along the slim type liquid-transporting body can be discharged from the through hole. The slim type liquid-transporting body may be bendable and/or able to be telescoped. To make the slim type liquid-transporting body bendable, then for example the liquid-transporting body may be made from a flexible material, or the slim type liquid-transporting body may be divided up transversely (substantially perpendicular to the longitudinal axis) into a plurality of sections, and these sections connected by joint members so as to be able to pivot relative to each other. In order to enable telescoping of the slim type liquid-transporting body, then for example the slim type liquid-transporting body may be divided up transversely into a plurality of sections, and these sections connected so as to be slidable lengthwise relative to each other.
In the case where a plurality of the slim type liquid-transporting bodies are secured to the attachment device, then these may be arranged independent from the attachment device, or may be formed integral with the attachment device. As a representative example of where the gutter body is attached integral with the attachment device, there is for example a gutter body which is formed from a plate body which constitutes the attachment device, the gutter body being formed by bending opposite the whole of non horizontal side portions of the plate body along the side. In the case wherein the plate body constitutes the attachment device, normally, ideally, the plate body is in the shape of a triangle, an inverted trapezoid, or a quadrilateral such as a rectangle or square. However, there is not objection to plate bodies of shapes other than the above. With the gutter body formed in this manner, the respective shapes of the upper and lower openings are non symmetrical. With the plate body which constitutes the attachment device, the unbent flat portion acts as an agitator blade. To prevent the fluid resistance of the plate body constituting the attachment device becoming excessive, openings may be formed in the flat portion of the plate body to reduce the fluid resistance at this part. This is desirable.
The slim type liquid-transporting body is attached parallel with the agitator shaft or in a radiating arrangement with the lower opening closer to the agitator shaft than the upper opening. In the case of the latter, the slim type liquid-transporting body is preferably centripetally attached to the attachment device with the longitudinal axis coinciding with the radial direction in the revolution plane corresponding to the attachment location of the attachment device, because a large amount of liquid is ejected from the upper opening. This may be attached eccentrically, in a direction differing from the radial direction. In the case where the slim type liquid-transporting body is attached eccentrically, then the longitudinal axis of the slim type liquid-transporting body may be parallel with the radial direction in the revolution plane corresponding to the attachment location of the attachment device. Moreover this may be at an incline. In the case where this is eccentric and at an incline, then preferably the eccentricity is such that the lower opening of the liquid-transporting body leads at the time of revolution.
With the stout type liquid-transporting body, the upper base opening and the lower base opening are respectively the upper opening and the lower opening. The agitation shaft passes through the centers of the upper and lower openings. The stout type liquid-transporting body, and the agitator shaft are connected by the attachment device.
The liquid-transporting body may be secured to the attachment device at an inclination angle of a predetermined size, or may be mounted so that the size of the inclination angle can be optionally adjusted. The latter is preferable. Here the inclination angle, in the case of the slim type liquid-transporting body, is defined as the angle subtended between the longitudinal axis and the revolution plane of the slim type liquid-transporting body. Moreover, in the case of the stout type liquid-transporting body, this is defined as the angle subtended between the generating line of the wall of the tubular body and the revolution plane of the stout type liquid-transporting body. The method of securing may involve a routine procedure such as interference fitting, welding, or bonding. Here the longitudinal axis of the slim type liquid-transporting body is defined as the line connecting the respective centers or central points of the upper opening and lower opening of the liquid-transporting body.
Furthermore, the inclination angle of the liquid-transporting body is in the range from 0xc2x0 to 90xc2x0. As a result, with the slim type liquid-transporting body, the lower opening thereof is closer to the agitator shaft than the upper opening, or the distance from the agitator shaft to the lower opening and the upper opening is substantially the same for each. In practice however the former is preferable. In the case of the latter, when the slim type liquid-transporting body is a gutter body, then preferably the lower opening is covered over. In this case also, the liquid at the immersed portion of the gutter body is raised in the gutter body.
The inclination angle of the liquid-transporting body is appropriately selected according to the shape of the liquid-transporting body itself, the shape of the opening, the opening area ratio between the upper and the lower openings, the type of liquid, the revolution speed of the liquid-transporting body, the lift of the ejection liquid (the height reached by the ejection liquid on the inner peripheral surface of the tank peripheral wall; defined similarly hereunder), the ejection distance, and the ejection quantity. Normally, around 5xc2x0-85xc2x0 is suitable.
In order to mount the slim type liquid-transporting body on the agitator shaft so that the inclination angle can be adjusted, then for example this may be mounted with the lower end portion of the slim type liquid-transporting body hinged to the agitator shaft, and the upper opening of the slim type liquid-transporting body movable centripetally or centrifugally in the radial direction of the revolution plane by means of a vertical travelling device or a horizontal travelling device. Here the vertical travelling device and the horizontal travelling device are respectively, a device whereby the upper portion (the free end) of the slim type liquid-transporting body is lifted up or pushed down vertically to thereby adjust the inclination angle of the slim type liquid-transporting body, and a device whereby the upper portion (the free end) of the slim type liquid-transporting body is pulled in or pushed out horizontally to thereby adjust the inclination angle of the slim type liquid-transporting body. In the above, movement of the upper opening of the slim type liquid-transporting body is by a vertical travelling device or by a horizontal travelling device. Hereunder these are referred to as a vertical system and a horizontal system respectively.
The slim type liquid-transporting body can be inclined by making the length of the slim type liquid-transporting body longer than the radius in the revolution plane thereof, hinging the lower end of the transporting body to the agitator shaft, and slidingly contacting the upper end thereof against the inner peripheral surface of the tank. In this case, the inclination angle of the slim type liquid-transporting body can be adjusted by changing the length thereof. Moreover, by making the length of the slim type liquid-transporting body longer than the coil diameter of the coiled pipe installed in the tank (the distance from the center of the coiled pipe to the inside circumference), and hinging the lower end of the transporting body to the agitator shaft, the slim type liquid-transporting body can be inclined by slidingly contacting the lower end thereof against the upper end inner peripheral surface of the coiled pipe. In this case, by changing the attachment position of lower end of the slim type liquid-transporting body (the distance from the tank bottom surface), the inclination angle of the slim type liquid-transporting body can be adjusted.
The attachment device with the liquid-transporting body attached thereto is attached to the agitator shaft, with the lower opening of the liquid-transporting body immersed beneath the liquid surface, and the upper opening exposed from the liquid surface. By rotating the agitator shaft and hence revolving the liquid-transporting body, the liquid at the immersed portion of the liquid-transporting body is raised inside the liquid-transporting body in accordance with Bernoulli""s theorem, and due to centrifugal force, and is ejected from the upper opening. Together with this, the portion of the liquid-transporting body beneath the liquid surface acts as an agitator blade, and the liquid is agitated by this portion.
In the stout type liquid-transporting body, the upper base opening and the lower base opening respectively constitute the upper opening and the lower opening, and the inner peripheral surface of the tubular body of stout type liquid-transporting body constitutes the liquid flow path.
With the liquid ejection method of the present invention, the revolutional speed of the liquid-transporting body is appropriately selected depending on the liquid depth inside the tank, the inclination angle of the liquid-transporting body, the type of liquid-transporting body, the shape and size (stout or slim) of the liquid-transporting body, and the type of liquid.
Revolution of the liquid-transporting body makes liquid level up at the circumferencial surface of the tank wall but down around the agitator shaft to form a funnel shape, until the liquid level is lower than the lower opening of the liquid-transporting body and no raise of liquid is seen. At this time, the liquid level is returned to the usual by revolving the transporting body in a reverse direction. The rotational speed of the agitator shaft is increased in accordance with the drop in the liquid level inside the tank, and corresponding to this, the revolutional speed of the liquid-transporting body is also increased.
In this way, the liquid inside the tank is distributed into the space above the liquid surface in the tank interior and/or to a location at a desired height on the inner peripheral surface of the tank.
The liquid ejected from the upper opening of the liquid-transporting body is used for the following;
(a) for distributing onto the foam layer formed on the surface of the liquid inside the tank to disperse the foam;
(b) for distributing onto the inner peripheral surface of the tank to wash the inner peripheral surface thereof;
(c) for distributing onto the heat transfer surface of the heating and cooling equipment installed inside the tank to thereby wash the heat transfer surface;
(d) in the case where the liquid level in the tank drops, for distributing onto the inner peripheral surface of the tank which serves as a heat transfer surface, or onto the heat transfer surface of the heating or cooling equipment installed inside the tank, to maintain the heat transfer area; and/or
(e) for distributing into the space above the liquid surface inside the tank to promote evaporation of the liquid inside the tank.
In the case of e) above, the tank may be kept under reduced pressure or under pressure. In the former case, the liquid drops distributed boil immediately and evaporate. In the case of c), the liquid forms a film on the heat transfer surface and is heated or cooled in a short time. Time for heating or cooling liquid is shortened to save energy loss.
There is no particular restriction to the size of the liquid ejection apparatus of the present invention, and this may be an optional size. Normally, when used for example inside a large size tank at a manufacturing plant of a factory, then a large scale device is desirable, while when used for example inside a small-scale flask, then this can be a laboratory type small scale apparatus.
With the liquid ejection apparatus of the present invention installed inside a flask, then either of the slim type liquid-transporting body and the stout type liquid-transporting body can be used. In the case where the liquid-transporting body is the slim type liquid-transporting body, the upper end thereof is first moved close to the agitator shaft so that the inclination angle of the liquid-transporting body approaches 90xc2x0. Then after making the liquid-ejection apparatus narrow in this way, this is passed through the opening of the flask and installed inside the flask. After this, the liquid-transporting body is opened and secured at the desired inclination angle. Moreover, the upper end of the slim type liquid-transporting body may be slidingly contacted against the surface of the flask to give a predetermined inclination angle. Furthermore, the inclination angle of the slim type liquid-transporting body can be adjusted by the vertical system while inside the flask. In the case where the liquid-transporting body is the stout type liquid transporting body, then the flask is normally a separable flask. The liquid may be viscous one or suspension having large concentration of dispersoid.
Other objects and aspects of the present invention will become apparent from the following description of embodiments, given in conjunction with the appending drawings.